1. Field of the Invention
This invention relates generally to magnetic recording disk drives.
2. Description of the Related Art
In conventional magnetic recording disk drives the disks have concentric data tracks with regions in the data tracks magnetized in the circumferential or along-the-track direction. Data is recorded or written when these regions are magnetized by an inductive write head. The write head has write poles that generate a magnetic write field across a write gap in the along-the-track direction as the disk rotates past the write head. The written data “bits” are the transitions between successive magnetized regions in the data tracks. These transitions result in magnetic fields that are generally perpendicularly into or out of the disk. The written data bits are read back when these fields are detected by a magnetoresistive read head and processed by the disk drive's circuitry into data as the disk rotates past the read head.
The conventional magnetic recording disk drive has an inherent limitation in data recording density because the magnetized regions are magnetized along-the-track. Because the magnetized regions along a data track magnetically oppose each in the along-the-track direction, each magnetized region is exposed to demagnetizing fields from adjacent magnetized regions which affect the stability of the recorded data. The effect of these demagnetizing fields becomes more pronounced as the data bits become smaller in an attempt to increase the bit density in the data tracks.
What is needed is a magnetic recording disk drive that can have increased data recording density because it does not suffer from the problem associated with demagnetizing fields along the data tracks.